Common Shares (Details) - shares	Dec. 31, 2017	Dec. 31, 2016
Shares issued	24,777,001	23,800,924
Shares outstanding	24,132,910	23,446,035
Reserved For Issuance Upon Exercise Or Vesting Of Equity Awards
Number of shares reserved for future issuance	4,400,676
Stock options \| Reserved For Issuance Upon Exercise Or Vesting Of Equity Awards
Number of shares reserved for future issuance	1,116,750
Nil Coupon Perpetual Loan Notes
Number of shares reserved for future issuance	6,715

Aggregate number of common shares reserved for future issuance.

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- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

+ References

+ Details

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- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644

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- Details

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